Choosing an unrated roofing material for your roof replacement may appear as if you’ve saved money for now, but this also means your home won’t have any fire resistance. The material you choose may not even pass the requirements for the lowest-rated materials, which is not advisable to use according to most building codes.
You wouldn’t want to risk your home’s safety, so make sure you get a roof that’s rated. To help you decide, trusted roofing company Fields Roof Service explains the three categories of roofing materials:
Class A roofs are the preferred choice for homes today. It’s especially recommended if you live in areas that are prone to wildfires because only Class A roofs can withstand a burning brand measuring 12 in x 12 in and weighing 2,000 grams. They’ll last around two to four hours before it gets ignited. Class A roofs typically experience a maximum flame spread of six feet and endure 15 cycles of a gas flame turned on and off.
In residential roofing, a roof with a Class B rating is common in pressure-treated shakes and shingles. A roof that has this rating is still highly effective against moderate fire exposures and can experience a maximum flame spread of eight feet. They last about an hour before ignition and can resist eight cycles of a gas flame turned on and off. They can also withstand a burning brand weighing 500 grams and measuring 6 in by 6 in.
As the lowest of the three ratings, Class C roofs only offer light fire protection. They can experience a maximum flame spread of 13 feet and last 20 minutes before ignition. They can also withstand a burning brand weighing 1/4 gram and measuring 1.5 in x 1.5 in. With a gas flame turned on and off, it can only resist about three cycles.